Forgetting rate is related to average priority of an elements in Bag. Such a forgetting rate might help achieve a desired priority distribution of elements within the Bag.
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The budget of an element does decay (in Budget_decay()) after it is used. However, the formula is not related to the average priority of the Bag.
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The budget of an element does decay (in Budget_decay()) after it is used. However, the formula is not related to the average priority of the Bag.